Fig. 3

Effect of Nodal or BMP on animal pole blastomeres. (A) Injection of nodal RNA in an animal pole blastomere at the 128- to 256-cell stage results in the formation of ectopic axial structures (arrow) that express shh, a marker of the notochord and floor plate (inset). (B) Localization of the clone derived from the injected blastomere visualized by fluorescence resulting from the translation of gfp RNA co-injected with nodal RNA. (C) Injection of bmp4 RNA in an animal pole blastomere at the 128- to 256-cell stage has no effect on the morphology of the embryo. (D) Cells derived from the injected blastomere are all located in the epidermis. (E) Injection of nodal and bmp4 RNAs in an animal pole blastomere at the 128- to 256-cell stage results in the formation of an ectopic tail. (F) Localization of the clone derived from the injected blastomere visualized by fluorescence resulting from the translation of gfp RNAs co-injected with nodal and bmp4 RNAs.